public void GetDataSource(Register register, VirtualMemory memory, ref int returnVal, Error error)
{
switch (mode)
{
case CPUMode.RegisterOnly:
case CPUMode.RegisterToMemory:
case CPUMode.RegisterToRegister:
switch (destRegister)
{
case RegisterIndex.ax:
returnVal = register.ax;
break;
case RegisterIndex.bx:
returnVal = register.bx;
break;
case RegisterIndex.cx:
returnVal = register.cx;
break;
case RegisterIndex.dx:
returnVal = register.dx;
break;
case RegisterIndex.si:
returnVal = register.si;
break;
case RegisterIndex.di:
returnVal = register.di;
break;
case RegisterIndex.bp:
returnVal = register.bp;
break;
case RegisterIndex.sp:
returnVal = register.sp;
break;
case RegisterIndex.ip:
returnVal = register.ip;
break;
default:
error.cpuError = CPUError.NotDefinedRegisterError;
break;
}
break;
case CPUMode.MemoryToRegister:
case CPUMode.MemoryToMemory:
case CPUMode.MemoryOnly:
if (isSourceMemoryIndexIsRegister || isDestMemoryIndexIsRegister)
{
switch (sourceRegister)
{
case RegisterIndex.ax:
sourceMemoryIndex = register.ax;
break;
case RegisterIndex.bx:
sourceMemoryIndex = register.bx;
break;
case RegisterIndex.cx:
sourceMemoryIndex = register.cx;
break;
case RegisterIndex.dx:
sourceMemoryIndex = register.dx;
break;
case RegisterIndex.si:
sourceMemoryIndex = register.si;
break;
case RegisterIndex.di:
sourceMemoryIndex = register.di;
break;
case RegisterIndex.bp:
sourceMemoryIndex = register.bp;
break;
case RegisterIndex.sp:
sourceMemoryIndex = register.sp;
break;
case RegisterIndex.ip:
sourceMemoryIndex = register.ip;
break;
default:
error.cpuError = CPUError.NotDefinedRegisterError;
break;
}
}
returnVal = memory.GetData(sourceMemoryIndex, error);
break;
case CPUMode.NumberToMemory:
case CPUMode.NumberToRegister:
case CPUMode.NumberOnly:
returnVal = value;
break;
default:
returnVal = -1;
error.cpuError = CPUError.NotDefinedRegisterError;
break;
}
}
public void InstructionPerClock()
{
int source = 1, dest = 1, result = 1;
if (machineCodes == null)
{
Debug.Log("CPU Error");
error.cpuError = CPUError.NotDefinedMachineCode;
return;
}
if (machineCodes.Count <= register.ip)
{
Debug.Log("CPU Error");
error.cpuError = CPUError.IndexOutOfRangeFromInstructions;
isRun = false;
return;
}
//fetch Machine Code
currentCode = machineCodes[register.ip];
register.ip += 1;
Debug.Log("-----------------------");
Debug.Log("Instruction:" + currentCode.instruction + " Mode:" + currentCode.mode);
Debug.Log("AX:" + register.ax + " BX:" + register.bx);
Debug.Log("SP:" + register.sp + " IP:" + register.ip);
//decoding the instructions and execute
switch (currentCode.instruction)
{
case Instructions.MOV:
GetDataSource(ref source);
SetData(source);
break;
case Instructions.PUSH:
memory.SetData(register.sp, currentCode.value, error);
register.sp += 1;
break;
case Instructions.POP:
result = memory.GetData(register.sp, error);
SetData(result);
register.sp--;
break;
case Instructions.INC:
GetDataDest(ref source);
result = source + 1;
SetData(result);
break;
case Instructions.DEC:
GetDataDest(ref source);
result = source - 1;
SetData(result);
break;
case Instructions.ADD:
GetDataSource(ref source);
GetDataDest(ref dest);
result = source + dest;
SetData(result);
break;
case Instructions.SUB:
GetDataSource(ref source);
GetDataDest(ref dest);
source = -source;
result = source + dest;
SetData(result);
break;
case Instructions.MUL:
GetDataSource(ref source);
GetDataDest(ref dest);
result = source * dest;
SetData(result);
break;
case Instructions.XOR:
GetDataSource(ref source);
GetDataDest(ref dest);
result = source ^ dest;
SetData(result);
break;
case Instructions.OR:
GetDataSource(ref source);
GetDataDest(ref dest);
result = source | dest;
SetData(result);
break;
case Instructions.AND:
GetDataSource(ref source);
GetDataDest(ref dest);
result = source & dest;
SetData(result);
break;
case Instructions.SAL:
GetDataSource(ref source);
GetDataDest(ref dest);
result = source << dest;
SetData(result);
break;
case Instructions.SAR:
GetDataSource(ref source);
GetDataDest(ref dest);
result = source >> dest;
SetData(result);
break;
case Instructions.CMP:
GetDataSource(ref source);
GetDataDest(ref dest);
source = -source;
result = source + dest;
break;
case Instructions.TEST:
GetDataSource(ref source);
GetDataDest(ref dest);
result = source & dest;
break;
case Instructions.JMP:
GetDataSource(ref result);
register.ip = result;
break;
case Instructions.JE:
if (register.zf)
{
GetDataSource(ref result);
register.ip = result;
}
break;
case Instructions.JNE:
if (!register.zf)
{
GetDataSource(ref result);
register.ip = result;
}
break;
case Instructions.JS:
if (register.sf)
{
GetDataSource(ref result);
register.ip = result;
}
break;
case Instructions.JNS:
if (!register.sf)
{
GetDataSource(ref result);
register.ip = result;
}
break;
case Instructions.JG:
if (!(register.sf ^ register.of) & !register.zf)
{
GetDataSource(ref result);
register.ip = result;
}
break;
case Instructions.JGE:
if (!(register.sf ^ register.of))
{
GetDataSource(ref result);
register.ip = result;
}
break;
case Instructions.JL:
if (register.sf ^ register.of)
{
GetDataSource(ref result);
register.ip = result;
}
break;
case Instructions.JLE:
if ((register.sf ^ register.of) | register.zf)
{
GetDataSource(ref result);
register.ip = result;
}
break;
case Instructions.END:
isRun = false;
break;
default:
error.cpuError = CPUError.NotDefinedMachineCode;
isRun = false;
break;
}
register.SetCarryFlag(result, dest, source);
}
public int AccessMemory(int index)
{
return(memory.GetData(index, error));
}
